How Five Prime suitor Amgen battled multiple companies for the biotech—and won

At the start of the month, Amgen stepped up with a $1.9 billion deal to buy out long-suffering Five Prime, a biotech that has seen failure and setback again and again over the years but that was handed a reprieve when its cancer drug bemarituzumab showed some positive phase 2 data late last year, sending its shares rocketing up by 300%.